1. Field of the Invention
The present invention relates to a novelty drinking cup or mug assembly that allows an individual to choose and change the ornamental design of the mug. In particular, the present invention relates to a drinking mug assembly that comprises two mugs, an internal mug and a transparent external mug. A decorative mat or piece or color particles suspended in a liquid may be provided between the internal and the external mugs, or the exterior of the internal mug may be decorated with a desired design or pattern.
2. Description of the Related Art
The present invention is applicable to mugs, cups and beverage containers alike, which shall hereinafter be collectively referred to as "mugs".
Certain conventional novelty drinking mug assemblies are very popular with children and adults alike. Such novelty drinking mug assemblies comprise two mugs, an internal mug and a substantially transparent external mug, with a decorative mat or piece provided in the space between the internal and the external mugs. The internal mug has an overhanging lip portion that is adapted to engage the lip at the mouth of the external mug. The decorative mat or piece may be a sheet of paper or fabric having an ornamental design, words, or a combination thereof, etched, printed or otherwise disposed on it. The decorative mat is fitted inside the external mug against the inside surfaces of the external mug. The internal mug is positioned inside the external mug, and the overhanging lip of the internal mug overhangs and engages the mouth of the external mug to hold the decorative mat in place between the two mugs. Instead of a decorative mat, some novelty drinking mug assemblies have provided particles of different colors that are suspended in a liquid that is captured between the two mugs.
These novelty drinking mug assemblies are popular because they allow an individual to choose or change the ornamental design of the drinking mug assembly. For instance, an individual may provide a decorative piece of paper having a particular ornamental design or written message. At a later time, this same individual may decide to sew an ornamental pattern onto a fabric or other mat, and then substitute this mat for the previous piece of decorative paper. Thus, the individual is provided with an unlimited variety of different ornamental designs and messages that he or she can provide to the same drinking mug assembly.
The internal and external mugs of such conventional novelty drinking mug assemblies are typically made from plastic. In particular, the external mug must be made from a substantially transparent material to allow the decorative mat or suspended color particles to be visible. The internal mug can be any color but preferably a neutral color so as to provide a good background for the decorative mat or suspended color particles. In any case, plastic is typically used for both the internal and the erternal mugs because plastic can be easily molded to form the desired overhanging lip and to ensure an effective snap-fit engagement between the overhanging lip of the internal mug and the mouth of the external mug. This snap-fit engagement is easily accomplished because plastic is a flexible material which can be flexed or deformed to snap the overhanging lip over the mouth of the external mug.
Unfortunately, the use of plastic as a material for a cup or mug has several drawbacks. First, plastic surfaces are often more difficult to clean effectively than surfaces made from other materials such as ceramic, glass or porcelain. Second, people have complained that plastic mugs impart an unpleasant odor, while ceramic, glass or porcelain mugs do not carry such an odor. Third, plastic is not effective in retaining the temperature of the fluid contained in the mug, while ceramic, glass or porcelain mugs are somewhat more effective in retaining the temperature of the fluid. Fourth, plastic mugs are susceptible to leakage due to cracks or other deformities, so that when used with the novelty drinking mug assemblies described above, there is a danger that contaminants or the liquid captured between the two mugs may leak into the drinking liquid if the internal mug leaks or is deformed. For the purposes of the present invention, the term "plastic" is meant to include flexible, lightweight, synthetic materials such as polyethylene, polypropylene, or similar materials.
Despite these recognized drawbacks of plastic, both the internal and the external mugs of these novelty drinking mug assemblies are still made from plastic because the other materials such as ceramic, glass or porcelain are not flexible enough to provide an effective snap-fit engagement mechanism between the internal and the external mugs. Thus, there is still a need for a novelty drinking mug assembly in which at least the internal mug, and preferably also the external mug, are made of a non-plastic material such as ceramic, porcelain or glass, and which provides a safe, effective, and convenient mechanism for engaging the internal and external mugs to hold a decorative mat or liquid therebetween.